(a) Field of the Invention
The present invention relates to a display device. More specifically, the present invention relates to a demultiplexer for demultiplexing the data current in a display device.
(b) Description of the Related Art
FIG. 1 shows an active matrix organic light emitting diode (AMOLED) display device as an example of a current driven display device which needs current demultiplexing. Exemplary embodiments of the present invention can be applied to the AMOLED display device of FIG. 1, as well as other suitable current driven display devices.
The current driven display device of FIG. 1 includes an organic electroluminescent (EL) display panel 100, a data driver 200 for providing a data current, a current demultiplexer 300 for performing a 1:N ratio demultiplexing on the data current, and scan drivers 400 and 500 for sequentially selecting a plurality of scan lines.
A predetermined data current is applied to pixels 10 belonging to scan lines selected by the scan drivers 400 and 500, and the pixels 10 display colors corresponding to the data current. The current demultiplexer 300 is used to reduce the number of ICs (integrated circuits) of the data driver 200. That is, the current provided by the data driver 200 is 1:N-demultiplexed by the demultiplex unit 300, and is applied to the pixels corresponding to the N data lines. Usage of the current demultiplexer 300 reduces the number of ICs necessary for the data driver and saves purchase costs.
FIG. 2 shows a conventional analog switch for a demultiplexer.
The 1:2 demultiplexer shown in FIG. 2 alternately turns on and off the switches S1 and S2 to thereby output the data current to two data lines. A long time is required to program the data to the pixels 10 in order to realize high resolution in the current driven panel. Therefore, a problem with reducing the number of ICs of the data driver is that the data programming time needs to be reduced because the data are to be programmed to the pixels each time the switches are alternately turned on and off. Thus, the conventional demultiplexer is not suitable for high-resolution display devices that require a long data programming time.